# Changelog for [`base` package](http://hackage.haskell.org/package/base)
## 4.7.0.1 *Jul 2014*
* Bundled with GHC 7.8.3
* Unhide `Foreign.ForeignPtr` in Haddock (#8475)
* Fix recomputation of `TypeRep` in `Typeable` type-application instance
(#9203)
* Fix regression in Data.Fixed Read instance (#9231)
* Fix `fdReady` to honor `FD_SETSIZE` (#9168)
## 4.7.0.0 *Mar 2014*
* Bundled with GHC 7.8.1
* Add `/Since: 4.[4567].0.0/` Haddock annotations to entities
denoting the package version, when the given entity was introduced
(or its type signature changed in a non-compatible way)
* The `Control.Category` module now has the `PolyKinds` extension
enabled, meaning that instances of `Category` no longer need be of
kind `* -> * -> *`.
* There are now `Foldable` and `Traversable` instances for `Either a`,
`Const r`, and `(,) a`.
* There is now a `Monoid`, `Generic`, and `Generic1` instance for `Const`.
* There is now a `Data` instance for `Data.Version`.
* A new `Data.Bits.FiniteBits` class has been added to represent
types with fixed bit-count. The existing `Bits` class is extended
with a `bitSizeMaybe` method to replace the now obsolete
`bitsize` method.
* `Data.Bits.Bits` gained a new `zeroBits` method which completes the
`Bits` API with a direct way to introduce a value with all bits cleared.
* There are now `Bits` and `FiniteBits` instances for `Bool`.
* There are now `Eq`, `Ord`, `Show`, `Read`, `Generic`. and `Generic1`
instances for `ZipList`.
* There are now `Eq`, `Ord`, `Show` and `Read` instances for `Down`.
* There are now `Eq`, `Ord`, `Show`, `Read` and `Generic` instances
for types in GHC.Generics (`U1`, `Par1`, `Rec1`, `K1`, `M1`,
`(:+:)`, `(:*:)`, `(:.:)`).
* `Data.Monoid`: There are now `Generic` instances for `Dual`, `Endo`,
`All`, `Any`, `Sum`, `Product`, `First`, and `Last`; as well as
`Generic1` instances for `Dual`, `Sum`, `Product`, `First`, and `Last`.
* The `Data.Monoid.{Product,Sum}` newtype wrappers now have `Num` instances.
* There are now `Functor` instances for `System.Console.GetOpt`'s
`ArgOrder`, `OptDescr`, and `ArgDescr`.
* A zero-width unboxed poly-kinded `Proxy#` was added to
`GHC.Prim`. It can be used to make it so that there is no the
operational overhead for passing around proxy arguments to model
type application.
* New `Data.Proxy` module providing a concrete, poly-kinded proxy type.
* New `Data.Coerce` module which exports the new `Coercible` class
together with the `coerce` primitive which provide safe coercion
(wrt role checking) between types with same representation.
* `Control.Concurrent.MVar` has a new implementation of `readMVar`,
which fixes a long-standing bug where `readMVar` is only atomic if
there are no other threads running `putMVar`. `readMVar` now is
atomic, and is guaranteed to return the value from the first
`putMVar`. There is also a new `tryReadMVar` which is a
non-blocking version.
* New `Control.Concurrent.MVar.withMVarMasked` which executes
`IO` action with asynchronous exceptions masked in the same style
as the existing `modifyMVarMasked` and `modifyMVarMasked_`.
* New `threadWait{Read,Write}STM :: Fd -> IO (STM (), IO ())`
functions added to `Control.Concurrent` for waiting on FD
readiness with STM actions.
* Expose `Data.Fixed.Fixed`'s constructor.
* There are now byte endian-swapping primitives
`byteSwap{16,32,64}` available in `Data.Word`, which use
optimized machine instructions when available.
* `Data.Bool` now exports `bool :: a -> a -> Bool -> a`, analogously
to `maybe` and `either` in their respective modules.
* `Data.Either` now exports `isLeft, isRight :: Either a b -> Bool`.
* `Debug.Trace` now exports `traceId`, `traceShowId`, `traceM`,
and `traceShowM`.
* `Data.Functor` now exports `($>)` and `void`.
* Rewrote portions of `Text.Printf`, and made changes to `Numeric`
(added `Numeric.showFFloatAlt` and `Numeric.showGFloatAlt`) and
`GHC.Float` (added `formatRealFloatAlt`) to support it. The
rewritten version is extensible to user types, adds a "generic"
format specifier "`%v`", extends the `printf` spec to support much
of C's `printf(3)` functionality, and fixes the spurious warnings
about using `Text.Printf.printf` at `(IO a)` while ignoring the
return value. These changes were contributed by Bart Massey.
* The minimal complete definitions for all type-classes with cyclic
default implementations have been explicitly annotated with the
new `{-# MINIMAL #-}` pragma.
* `Control.Applicative.WrappedMonad`, which can be used to convert a
`Monad` to an `Applicative`, has now a
`Monad m => Monad (WrappedMonad m)` instance.
* There is now a `Generic` and a `Generic1` instance for `WrappedMonad`
and `WrappedArrow`.
* Handle `ExitFailure (-sig)` on Unix by killing process with signal `sig`.
* New module `Data.Type.Bool` providing operations on type-level booleans.
* Expose `System.Mem.performMinorGC` for triggering minor GCs.
* New `System.Environment.{set,unset}Env` for manipulating
environment variables.
* Add `Typeable` instance for `(->)` and `RealWorld`.
* Declare CPP header `` officially obsolete as GHC 7.8+
does not support hand-written `Typeable` instances anymore.
* Remove (unmaintained) Hugs98 and NHC98 specific code.
* Optimize `System.Timeout.timeout` for the threaded RTS.
* Remove deprecated functions `unsafeInterleaveST`, `unsafeIOToST`,
and `unsafeSTToIO` from `Control.Monad.ST`.
* Add a new superclass `SomeAsyncException` for all asynchronous exceptions
and makes the existing `AsyncException` and `Timeout` exception children
of `SomeAsyncException` in the hierarchy.
* Remove deprecated functions `blocked`, `unblock`, and `block` from
`Control.Exception`.
* Remove deprecated function `forkIOUnmasked` from `Control.Concurrent`.
* Remove deprecated function `unsafePerformIO` export from `Foreign`
(still available via `System.IO.Unsafe.unsafePerformIO`).
* Various fixes and other improvements (see Git history for full details).